<!DOCTYPE HTML>
<html>
<head>
  <title>Test the OscillatorNode when the frequency is negative</title>
  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
  <script type="text/javascript" src="webaudio.js"></script>
  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
</head>
<body>
<pre id="test">
<script class="testbody" type="text/javascript">

SimpleTest.waitForExplicitFinish();
addLoadEvent(function() {

  var types = ["sine",
               "square",
               "sawtooth",
               "triangle"];

  var finished = 0;
  function finish() {
    if (++finished == types.length) {
      SimpleTest.finish();
    }
  }

  types.forEach(function(t) {
    var context = new OfflineAudioContext(1, 256, 44100);
    var osc = context.createOscillator();

    osc.frequency.value = -440;
    osc.type = t;

    osc.connect(context.destination);
    osc.start();
    context.startRendering().then(function(buffer) {
      var samples = buffer.getChannelData(0);
      // This samples the wave form in the middle of the first period, the value
      // should be negative.
      ok(samples[Math.floor(44100 / 440 / 4)] < 0., "Phase should be inverted when using a " + t + " waveform");
      finish();
    });
  });
});

</script>
</pre>
</body>
</html>
